Method for the production of 1-amino-3-phenyluracil derivatives

ABSTRACT

The present invention relates to a novel process for preparing known 1-amino-3-phenyluracil derivatives, to novel 1-amino-6-hydroxy-3-phenyldihydro-2,4(1H,3H)pyrimidinedione derivatives of the formula (II)                  
 
in which
     R 1  is hydrogen, cyano, nitro or halogen,   R 2  is cyano, nitro, halogen or optionally substituted alkyl or alkoxy,   R 3  is hydrogen, hydroxyl, mercapto, amino, hydroxyamino, hydrazino, halogen, or one of the radicals —R 6 , -Q-R 6 , —NH—R 6 , —NH—O—R 6 , —NH—SO 2 —R 6 , —N(SO 2 —R 6 ) 2 , —CQ 1 -R 6 , —CQ 1 -Q 2 -R 6 , —CQ 1 -NH—R 6 , -Q 2 -CQ 1 -R 6 , —NH—CQ 1 -R 6 , —N(SO 2 —R 6 )(CQ 1 -R 6 ), -Q 2 -CQ 1 -Q 2 -R 6 , —NH—CQ 1 -Q 2 -R 6  or -Q 2 -CQ 1 -NH—R 6 ,
       where   Q is O, S, SO or SO 2 ,   Q 1  and Q 2  are each independently oxygen or sulphur and   R 6  is optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, heterocyclyl or heterocyclylalkyl,   
       R 4  is hydrogen, halogen or optionally substituted alkyl, and   R 5  is fluorine- and/or chlorine-substituted alkyl,
 
as intermediates for the 1-amino-3-phenyluracil derivatives, and to a process for preparing the intermediates.

The present patent application has been filed under 35 U.S.C. 371 as anational stage application of PCT/EP02/04610, filed Apr. 25, 2002, whichwas published in German as International Patent Publication WO02/090,338 on Nov. 14, 2002, which is entitled to the right of priorityof German Patent Application 101 22 235.1, filed May 8, 2001.

The present invention relates to a novel process for preparing known1-amino-3-phenyluracil derivatives(1-amino-3-phenyl-2,4(1H,3H)pyrimidinedione derivatives) and novel1-amino-6-hydroxy-3-phenyldihydro-2,4(1H,3H)pyrimidinedione derivativesas intermediates therefore and to a process for preparing them.

It has already become known that certain 3-amino-1-phenyluracils can beprepared by reacting amino alkenoic esters with substitutedphenylisocyanates or with substituted phenylurethanes in the presence ofbases and reacting the resulting 1-phenyluracils with1-aminooxy-2,4-dinitrobenzene (cf. EP-A-648 749, U.S. Pat. Nos.5,593,945, 5,681,794, 6,110,870, WO-A-95/29168, U.S. Pat. Nos.5,759,957, 5,962,372). However, a disadvantage of this process is thatthe desired products occur in relatively low yields and not always insufficient quality. Also, the starting materials required have littlesuitability for the preparation on the industrial scale.

It is further already known that certain 1,3-oxazine-2,4(3H)diones whichare unsubstituted on the nitrogen atom react with hydrazine to giveuracils which bear an amino group as substituents. In contrast, thecorresponding reaction of 1,3-oxazine-2,4(3H)diones which aresubstituted on the nitrogen atom results not in uracils but onlypyrazole derivatives (cf. J. Heterocycl. Chem. 15 (1978), 1475–1478).

Finally, it is already known that 3-amino-1-phenyluracil derivatives canalso be obtained by reacting substituted phenyloxazinediones withhydrazine hydrate or with acid adducts of hydrazine (cf. WO-A-98/27068).However, the yield and quality of the products obtained in this way arenot entirely satisfactory.

It has now been found that 1-amino-3-phenyluracil derivatives(1-amino-3-phenyl-2,4(1H,3H)pyrimidinedione derivatives) of the generalformula (I)

in which

-   R¹ is hydrogen, cyano, nitro or halogen,-   R² is cyano, nitro, halogen or optionally substituted alkyl or    alkoxy,-   R³ is hydrogen, hydroxyl, mercapto, amino, hydroxyamino, hydrazino,    halogen, or one of the radicals —R⁶, -Q-R⁶, —NH—R⁶, —NH—O—R⁶,    —NH—SO₂—R⁶, —N(SO₂—R⁶)₂, —CQ¹-R⁶, —CQ¹Q²-R⁶, —CQ¹-NH—R⁶, Q²-CQ¹-R⁶,    —NH—CQ¹-R⁶, —N(SO₂—R⁶)(CQ¹-R⁶), -Q²-CQ¹-Q²-R⁶, —NH—CQ¹-Q²-R⁶ or    -Q²-CQ¹-NH-R⁶,    -   where    -   Q is O, S, SO or SO₂,    -   Q¹ and Q² are each independently oxygen or sulphur and    -   R⁶ is optionally substituted alkyl, alkenyl, alkinyl,        cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, heterocyclyl or        heterocyclylalkyl,-   R⁴ is hydrogen, halogen or optionally substituted alkyl, and-   R⁵ is fluorine- and/or chlorine-substituted alkyl,    by reacting    1-amino-6-hydroxy-3-phenyldihydro-2,4(1H,3H)pyrimidinedione    derivatives of the general formula (II)

in which

-   R¹, R², R³, R⁴ and R⁵ are each as defined above    are reacted with a dehydrating agent, optionally in the presence of    one or more reaction assistants and optionally in the presence of    one or more diluents, at temperatures between −30° C. and +180° C.

Preferred definitions of the radicals and groups present in formula (I)are defined hereinbelow.

-   R¹ is preferably hydrogen, cyano, nitro, fluorine, chlorine or    bromine,-   R² is preferably cyano, nitro, fluorine, chlorine, bromine or    optionally fluorine- and/or chlorine-substituted alkyl or alkoxy    having 1 to 4 carbon atoms,-   R³ is preferably hydrogen, hydroxyl, mercapto, amino, hydroxyamino,    halogen, or one of the radicals —R⁶, -Q-R⁶, —NH—R⁶, —NH—O—R⁶,    —NH—SO₂—R⁶, —N(SO₂—R⁶)₂, —CQ¹-R⁶, —CQ¹-Q²-R⁶, —CQ¹-NH—R⁶,    -Q²-CQ¹-R⁶, —NH—CQ¹-R⁶, —N(SO₂—R⁶)(CQ¹-R⁶), -Q²-CQ¹-Q²-R⁶,    —NH—CQ¹-Q²-R⁶ or -Q²-CQ¹-NH-R⁶,-   Q is preferably O, S or SO₂,-   Q¹ and Q² are preferably each oxygen.-   R⁴ is preferably hydrogen, fluorine, chlorine, bromine or optionally    fluorine- and/or chlorine-substituted alkyl having 1 to 6 carbon    atoms.-   R⁵ is preferably fluorine- and/or chlorine-substituted alkyl having    1 to 6 carbon atoms.-   R⁶ is preferably optionally cyano-, halogen-, C₁–C₄-alkoxy-,    C₁–C₄-alkylthio-, C₁–C₄-alkylcarbonyl-, C₁–C₄-alkoxycarbonyl- or    C₁–C₄-alkylaminocarbonyl-substituted alkyl having 1 to 6 carbon    atoms,    -   or optionally cyano-, carboxy-, halogen-, C₁–C₄-alkylcarbonyl-,        C₁–C₄-alkoxycarbonyl- or C₁–C₄-alkylaminocarbonyl-substituted        alkenyl or alkinyl each having 2 to 6 carbon atoms,    -   or optionally cyano, carboxy, halogen, C₁–C₄-alkylcarbonyl- or        C₁–C₄-alkoxycarbonyl-substituted cycloalkyl or cycloalkylalkyl        each having 3 to 6 carbon atoms in the cycloalkyl group and        optionally 1 to 4 carbon atoms in the alkyl moiety,    -   or optionally mono- to tri-hydroxy-, -mercapto-, -amino-,        -cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-, —C₁–C₄-alkyl-,        —C₁–C₄-haloalkyl-, —C₁–C₄-alkoxy-, —C₁–C₄-haloalkoxy-,        —C₁–C₄-alkylthio-, —C₁–C₄-haloalkylthio-,        —C₁–C₄-alkylsulphinyl-, —C₁–C₄-alkylsulphonyl-,        —C₁–C₄-alkylamino- and/or -dimethylamino-substituted aryl or        arylalkyl each having 6 or 10 carbon atoms in the aryl group and        optionally 1 to 4 carbon atoms in the alkyl moiety,    -   or optionally mono- to tri-hydroxy-, -mercapto-, -amino-,        -cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-, —C₁–C₄-alkyl-,        —C₁–C₄-haloalkyl-, —C₁–C₄-alkoxy-, —C₁–C₄-haloalkoxy-,        —C₁–C₄-alkylthio-, —C₁–C₄-haloalkylthio-,        —C₁–C₄-alkylsulphinyl-, —C₁–C₄-alkylsulphonyl-,        —C₁–C₄-alkylamino- and/or -dimethylamino-substituted        heterocyclyl or heterocyclylalkyl having 2 to 6 carbon atoms and        1 to 3 nitrogen atoms and/or 1 or 2 oxygen atoms and/or one        sulphur atom in the heterocyclyl group and optionally 1 to 4        carbon atoms in the alkyl moiety.-   R¹ is more preferably hydrogen, fluorine or chlorine.-   R² is more preferably cyano, fluorine, chlorine, bromine, methyl or    trifluoromethyl.-   R³ is more preferably hydroxyl, mercapto, amino, fluorine, chlorine,    bromine or one of the radicals —R⁶, -Q-R⁶, —NH—R⁶, —NH—O—R⁶,    —NH—SO₂—R⁶, —N(SO₂—R⁶)₂, —CQ¹-R⁶, —CQ¹-Q²-R⁶, —CQ¹-NH—R⁶,    -Q²-CQ¹-R⁶, —NH—CQ¹-R⁶, —N(SO₂—R⁶)(CQ¹-R⁶), -Q²-CQ¹-Q²-R⁶,    —NH—CQ¹-Q²-R⁶ or -Q²-CQ¹-NH-R^(6.)-   Q is more preferably O or SO₂.-   R⁴ is more preferably hydrogen, fluorine, chlorine, bromine, methyl,    ethyl or trifluoromethyl.-   R⁵ is more preferably trifluoromethyl, chlorodifluoromethyl,    fluorodichloromethyl or pentafluoroethyl.-   R⁶ is more preferably optionally cyano-, fluorine-, chlorine-,    methoxy-, ethoxy-, methylthio-, ethylthio-, acetyl-, propionyl-,    methoxycarbonyl-, ethoxycarbonyl-, methylaminocarbonyl- or    ethylaminocarbonyl-substituted methyl, ethyl, n- or i-propyl, n-, i-    or s-butyl,    -   or optionally cyano-, carboxy-, fluorine-, chlorine-, bromine-,        acetyl-, propionyl-, n- or i-butyroyl-, methoxycarbonyl-,        ethoxycarbonyl-, n- or i-propoxycarbonyl-, methylaminocarbonyl-,        ethylaminocarbonyl-, n- or i-propylaminocarbonyl-substituted        propenyl, butenyl, propinyl or butinyl,    -   or optionally cyano-, carboxy-, fluorine-, chlorine-, bromine-,        acetyl-, propionyl-, methoxycarbonyl- or        ethoxycarbonyl-substituted cyclopropyl, cyclobutyl, cyclopentyl,        cyclohexyl, cyclopropylmethyl, cyclobutylmethyl,        cyclopentylmethyl or cyclohexylmethyl,    -   or optionally mono- to tri-hydroxy-, -mercapto-, -amino-,        -cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-, -methyl-,        -ethyl-, -trifluoromethyl-, -methoxy-, -ethoxy-,        -difluoromethoxy-, -trifluoromethoxy-, -methylthio-,        -ethylthio-, -difluoromethylthio-, -trifluoromethylthio-,        -methylsulphinyl-, -ethylsulphinyl-, -methylsulphonyl-,        -methylamino-, -ethylamino- and/or -dimethylamino-substituted        phenyl, benzyl or phenylethyl,    -   or optionally mono- or di-hydroxy-, -mercapto-, -amino-,        -cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-, -methyl-,        -ethyl-, -n- or -1-propyl-, -n-, -i-, -s- or -t-butyl-,        -difluoromethyl-, -dichloromethyl-, -trifluoromethyl-,        -trichloromethyl-, -chlorodifluoromethyl-,        -fluorodichloromethyl-, -methoxy-, -ethoxy-, -difluoromethoxy-,        -trifluoromethoxy-, -methylthio-, -ethylthio-,        -difluoromethylthio-, -trifluoromethylthio-, -methylsulphinyl-,        -ethylsulphinyl-, -methylsulphonyl-, -ethylsulphonyl-,        -methylamino-, -ethylamino- and/or -dimethylamino-substituted        heterocyclyl or heterocyclylalkyl from the group of oxiranyl,        oxetanyl, furyl, tetrahydrofuryl, dioxolanyl, thienyl,        tetrahydrothienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl,        oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, oxadiazolyl,        thiadiazolyl, pyridinyl, pyrimidinyl, triazinyl,        pyrazolylmethyl, furylmethyl, thienylmethyl, oxazolylmethyl,        isoxazolylmethyl, thiazolylmethyl, pyridinylmethyl,        pyrimidinylmethyl,

Surprisingly, the 1-amino-3-phenyluracil derivatives(1-amino-3-phenyl-2,4(1H,3H)-pyrimidinedione derivatives) of the generalformula (I) can be prepared by the process according to the invention inconsiderably better yields and in higher purity than by the processesknown hitherto.

The process according to the invention is notable for a series ofadvantages. For instance, the starting materials required are obtainablein a simple manner and also in relatively large amounts. In addition,carrying out the reaction according to the invention and the isolationof the desired substances presents no problems worthy of mention.

When the starting material used is1-amino-3-(4-cyano-2,5-difluorophenyl)dihydro-6-hydroxy-6-trifluoromethyl-2,4(1H,3H)pyrimidinedioneand the dehydrating agent used is oxalyl chloride, the course of theprocess according to the invention can be outlined by the followingscheme:

The 1-amino-6-hydroxy-3-phenyldihydro-1,4(1H,3H)-pyrimidinedionederivatives required as starting materials when carrying out the processaccording to the invention are generally defined by formula (II).Preference is given to using compounds of the formula (II) in which

-   R¹ is hydrogen, cyano, nitro, fluorine, chlorine or bromine,-   R² is cyano, nitro, fluorine, chlorine, bromine or optionally    fluorine- and/or chlorine-substituted alkyl or alkoxy having 1 to 4    carbon atoms,-   R³ is hydrogen, hydroxyl, mercapto, amino, hydroxyamino, halogen, or    one of the radicals —R⁶, -Q-R⁶, —NH—R⁶, —NH—O—R⁶, —NH—SO₂—R⁶,    —N(SO₂—R⁶)₂, —CQ¹-R⁶, —CQ¹-Q²-R⁶, —CQ¹-NH—R⁶, -Q²-CQ¹-R⁶,    —NH—CQ¹-R⁶, —N(SO₂—R⁶)(CQ¹-R⁶), -Q²-CQ¹-Q²-R⁶, —NH—CQ¹-Q²-R⁶ or    -Q²-CQ¹-NH-R⁶,    -   where    -   Q is O, S, SO or SO₂,    -   Q¹ and Q² are each independently oxygen or sulphur and    -   R⁶ is optionally cyano-, halogen-, C₁–C₄-alkoxy-,        C₁–C₄-alkylthio-, C₁–C₄-alkylcarbonyl-, C₁–C₄-alkoxycarbonyl- or        C₁–C₄-alkylaminocarbonyl-substituted alkyl having 1 to 6 carbon        atoms,        -   or optionally cyano-, carboxy-, halogen-,            C₁–C₄-alkylcarbonyl-, C₁–C₄-alkoxycarbonyl- or            C₁–C₄-alkylaminocarbonyl-substituted alkenyl or alkinyl each            having 2 to 6 carbon atoms,        -   or optionally cyano, carboxy, halogen, C₁–C₄-alkylcarbonyl-            or C₁–C₄-alkoxycarbonyl-substituted cycloalkyl or            cycloalkylalkyl each having 3 to 6 carbon atoms in the            cycloalkyl group and optionally 1 to 4 carbon atoms in the            alkyl moiety,        -   or optionally mono- to tri-hydroxy-, -mercapto-, -amino-,            -cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-,            —C₁–C₄-alkyl-, —C₁–C₄-haloalkyl-, —C₁–C₄-alkoxy-,            —C₁–C₄-haloalkoxy-, —C₁–C₄-alkylthio-,            —C₁–C₄-haloalkylthio-, —C₁–C₄-alkylsulphinyl-,            —C₁–C₄-alkylsulphonyl-, —C₁–C₄-alkylamino- and/or            -dimethylamino-substituted aryl or arylalkyl each having 6            or 10 carbon atoms in the aryl group and optionally 1 to 4            carbon atoms in the alkyl moiety,        -   or optionally mono- to tri-hydroxy-, -mercapto-, -amino-,            -cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-,            —C₁–C₄-alkyl-, —C₁–C₄-haloalkyl-, —C₁–C₄-alkoxy-,            —C₁–C₄-haloalkoxy-, —C₁–C₄-alkylthio-,            —C₁–C₄-haloalkylthio-, —C₁–C₄-alkylsulphinyl-,            —C₁–C₄-alkylsulphonyl-, —C₁–C₄-alkylamino- and/or            -dimethylamino-substituted heterocyclyl or heterocyclylalkyl            having 2 to 6 carbon atoms and 1 to 3 nitrogen atoms and/or            1 or 2 oxygen atoms and/or one sulphur atom in the            heterocyclyl group and optionally 1 to 4 carbon atoms in the            alkyl moiety,-   R⁴ is hydrogen, fluorine, chlorine, bromine or optionally fluorine-    and/or chlorine-substituted alkyl having 1 to 6 carbon atoms and-   R⁵ is fluorine- and/or chlorine-substituted alkyl having 1 to 6    carbon atoms.

Particularly preferred definitions of the radicals and groups present in(II) are defined hereinbelow.

-   R¹ is preferably hydrogen, fluorine or chlorine.-   R² is preferably cyano, fluorine, chlorine, bromine, methyl or    trifluoromethyl.-   R³ is preferably hydroxyl, mercapto, amino, fluorine, chlorine,    bromine or one of the radicals —R⁶, -Q-R⁶, —NH—R⁶, —NH—O—R⁶,    —NH—SO₂—R⁶, —N(SO₂—R⁶)₂, —CQ¹-R⁶, —CQ¹-Q²-R⁶, —CQ¹-NH—R⁶, Q²-CQ¹-R⁶,    —NH—CQ¹-R⁶, —N(SO₂—R⁶)(CQ¹-R⁶), -Q²-CQ¹-Q²-R⁶, —NH—CQ¹-Q²-R⁶ or    -Q²-CQ¹-NH-R⁶.-   Q is preferably O, S or SO₂.-   Q¹ and Q² are each independently preferably oxygen.-   R⁴ is preferably hydrogen, fluorine, chlorine, bromine, methyl,    ethyl or trifluoromethyl.-   R⁵ is preferably trifluoromethyl, chlorodifluoromethyl,    fluorodichloromethyl or pentafluoroethyl.-   R⁶ is preferably optionally cyano-, fluorine-, chlorine-, methoxy-,    ethoxy-, methylthio-, ethylthio-, acetyl-, propionyl-,    methoxycarbonyl-, ethoxycarbonyl-, methylaminocarbonyl- or    ethylaminocarbonyl-substituted methyl, ethyl, n- or i-propyl, n-, i-    or s-butyl,    -   or optionally cyano-, carboxy-, fluorine-, chlorine-, bromine-,        acetyl-, propionyl-, n- or i-butyroyl-, methoxycarbonyl-,        ethoxycarbonyl-, n- or i-propoxycarbonyl-, methylaminocarbonyl-,        ethylaminocarbonyl-, n- or i-propylaminocarbonyl-substituted        propenyl, butenyl, propinyl or butinyl,    -   or optionally cyano-, carboxy-, fluorine-, chlorine-, bromine-,        acetyl-, propionyl-, methoxycarbonyl- or        ethoxycarbonyl-substituted cyclopropyl, cyclobutyl, cyclopentyl,        cyclohexyl, cyclopropylmethyl, cyclobutylmethyl,        cyclopentylmethyl or cyclohexylmethyl,    -   or optionally mono- to tri-hydroxy-, -mercapto-, -amino-,        -cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-, -methyl-,        -ethyl-, -trifluoromethyl-, -methoxy-, -ethoxy-,        -difluoromethoxy-, -trifluoromethoxy-, -methylthio-,        -ethylthio-, -difluoromethylthio-, -trifluoromethylthio-,        -methylsulphinyl-, -ethylsulphinyl-, -methylsulphonyl-,        -methylamino-, -ethylamino- and/or -dimethylamino-substituted        phenyl, benzyl or phenylethyl,    -   or optionally mono- or di-hydroxy-, -mercapto-, -amino-,        -cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-, -methyl-,        -ethyl-, -n- or -i-propyl-, -n-, -i-, -s- or -t-butyl-,        -difluoromethyl-, -dichloromethyl-, -trifluoromethyl-,        -trichloromethyl-, -chlorodifluoromethyl-,        -fluorodichloromethyl-, -methoxy-, -ethoxy-, -difluoromethoxy-,        -trifluoromethoxy-, -methylthio-, -ethylthio-,        -difluoromethylthio-, -trifluoromethylthio-, -methylsulphinyl-,        -ethylsulphinyl-, -methylsulphonyl-, -ethylsulphonyl-,        -methylamino-, -ethylamino- and/or -dimethylamino-substituted        heterocyclyl or heterocyclylalkyl from the group of oxiranyl,        oxetanyl, furyl, tetrahydrofuryl, dioxolanyl, thienyl,        tetrahydrothienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl,        oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, oxadiazolyl,        thiadiazolyl, pyridinyl, pyrimidinyl, triazinyl,        pyrazolylmethyl, furylmethyl, thienylmethyl, oxazolylmethyl,        isoxazolylmethyl, thiazolylmethyl, pyridinylmethyl,        pyrimidinylmethyl.-   R¹ is more preferably hydrogen, fluorine or chlorine.-   R² is more preferably cyano.-   R³ is more preferably one of the radicals —NH—R⁶, —NH—O—R⁶,    NH—SO₂—R⁶-, —NH—CQ¹-R⁶ or —N(SO₂—R⁶)(CQ¹-R⁶).-   Q is more preferably O or SO₂.-   R⁶ is more preferably optionally fluorine- and/or    chlorine-substituted methyl, ethyl or n- or i-propyl,    -   or optionally cyano-, fluorine- and/or chlorine-substituted        propenyl or butenyl,    -   or optionally cyano-, fluorine-, chlorine- or acetyl-substituted        cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl,        cyclopentylmethyl or cyclohexylmethyl,    -   or optionally mono- to tri-hydroxy-, -carboxy-, -methyl-,        -ethyl-, -trifluoromethyl-, -methoxy- or -ethoxy-substituted        phenyl, benzyl or phenylethyl,    -   or optionally mono- or di-hydroxy-, -amino-, -methyl-, -ethyl-,        -trifluoromethyl-, -methoxy- or -ethoxy-substituted heterocyclyl        or heterocyclylalkyl from the group of furyl, tetrahydrofuryl,        thienyl, tetrahydrothienyl, pyrrolyl, pyrazolyl, imidazolyl,        triazolyl, thiazolyl, thiadiazolyl, pyrazolylmethyl,        furylmethyl, thienylmethyl or thiazolylmethyl.

The starting materials of the general formula (II) are not yet disclosedby the literature; as novel substances, they also form part of thesubject-matter of the present application.

The novel 1-amino-6-hydroxy-3-phenyldihydro-1,4(1H,3H)pyrimidinedionederivatives of the general formula (II) are obtained when3-phenyl-2H-1,3-oxazine-2,4-(3H)dione derivatives of the general formula(III)

in which

-   R¹, R², R³, R⁴ and R⁵ are each as defined above,    are reacted with hydrazine, hydrazine hydrate or an acid adduct of    hydrazine, for example hydrazine acetate, hydrazine hydrochloride or    hydrazine sulphate, preferably with hydrazine hydrate,    optionally in the presence of a reaction assistant and/or diluent,    for example acetic acid or propionic acid, at temperatures between    −30° C. and +100° C., preferably between −10° C. and +80° C.

The 3-phenyl-2H-1,3-oxazine-2,4(3H)dione derivatives of the generalformula (III) are known and/or can be prepared by processes known per se(cf. EP-A-371240, EP-A-638563, WO-A-98/27057, WO-A-98/27067,WO-A-98/27068).

The process according to the invention for preparing1-amino-3-phenyluracil derivatives(1-amino-3-phenyl-2,4(1H,3H)pyrimidinedione derivatives) of the generalformula (I) is carried out with the use of a dehydrating agent. Usefuldehydrating agents in this context are the customary water-removingsubstances. Preferred groups of dehydrating agents are: carbodiimides,e.g. dicyclohexylcarbodiimide, orthoesters, e.g. trimethyl or triethylorthoformate, acids, e.g. hydrochloric acid, sulphuric acid,methanesulphonic acid, benzenesulphonic acid, p-toluenesulphonic acid ortrifluoroacetic acid, acid anhydrides, e.g. acetic anhydride, propionicanhydride, phosphorus(V) oxide or sulphur trioxide, acid chlorides, e.g.phosgen, oxalyl chloride, thionyl chloride, sulphuryl chloride,phosphoryl chloride, phosphorus(V) chloride, diethyl chlorophosphate,acetyl chloride, chlorotrimethylsilane, methanesulphonyl chloride,benzenesulphonyl chloride, p-toluenesulphonyl chloride, or Lewis acids,e.g. boron trifluoride or aluminium trichloride.

Very particular preference is given to using thionyl chloride as thedehydrating agent in the process according to the invention.

The process according to the invention for preparing1-amino-3-phenyluracil derivatives(1-amino-3-phenyl-2,4(1H,3H)pyrimidinedione derivatives) of the generalformula (I) is carried out using one or more reaction assistants. Usefulreaction assistants when carrying out the process according to theinvention are all customary inorganic or organic bases. Preference isgiven to using alkali metal or alkaline earth metal, acetates, amides,carbonates, hydrogen carbonates, hydrides, hydroxides or alkoxides, forexample sodium acetate, potassium acetate or calcium acetate, lithiumamide, sodium amide, potassium amide or calcium amide, sodium carbonate,potassium carbonate or calcium carbonate, sodium hydrogencarbonate,potassium hydrogencarbonate or calcium hydrogencarbonate, lithiumhydride, sodium hydride, potassium hydride or calcium hydride, lithiumhydroxide, sodium hydroxide, potassium hydroxide or calcium hydroxide,sodium or potassium methoxide, ethoxide, n- or i-propoxide, n-, i-, s-or t-butoxide; and also basic organic nitrogen compounds, for exampletrimethylamine, triethylamine, tripropylamine, tributylamine,ethyl-diisopropylamine, N,N-dimethylcyclohexylamine, dicyclohexylamine,ethyldicyclohexylamine, N,N-dimethylaniline, N,N-dimethylbenzylamine,pyridine, 2-methyl-, 3-methyl-, 4-methyl-, 2,4-dimethyl-, 2,6-dimethyl-,3,4-dimethyl- and 3,5-dimethylpyridine, 5-ethyl-2-methylpyridine,4-dimethylaminopyridine, N-methylpiperidine, N-ethylpiperidine,N-methylmorpholine, N-ethylmorpholine, 1,4-diazabicyclo[2,2,2]octane(DABCO), 1,5-diazabicyclo[4,3,0]non-5-ene (DBN), or1,8-diazabicyclo[5,4,0]undec-7-ene (DBU).

The abovementioned basic organic nitrogen compounds, in particularpyridine, are used with very particular preference as reactionassistants in the process according to the invention.

The process according to the invention for preparing1-amino-3-phenyluracil derivatives(1-amino-3-phenyl-2,4(1H,3H)pyrimidinedione derivatives) of the generalformula (I) is carried out using one or more diluents. Useful diluentswhen carrying out the process according to the invention are allcustomary inert, organic solvents.

Preference is given to using aliphatic, alicyclic or aromatic,optionally halogenated hydrocarbons, for example benzine, benzene,toluene, xylene, chlorobenzene, dichlorobenzene, petroleum ether,hexane, cyclohexane, dichloromethane, chloroform, carbon tetrachloride;ethers such as diethyl ether, diisopropyl ether, dioxane,tetrahydrofuran or ethylene glycol dimethyl or diethyl ether; ketonessuch as acetone, butanone or methyl isobutyl ketone; nitriles such asacetonitrile, propionitrile or n- or i-butyronitrile; amides such asN,N-dimethylformamide, N,N-diethylformamide, N,N-dipropylformamide,N,N-dibutylformamide, N,N-dimethylacetamide, N-methylformanilide,N-methylpyrrolidone or hexamethylphosphoramide; esters such as methylacetate or ethyl acetate, sulphoxides such as dimethyl sulphoxide.

Very particular preference is given to using aprotic polar solvents, forexample methyl isobutyl ketone, acetonitrile, propionitrile or n- ori-butyronitrile, N,N-dimethylformamide or N,N-dimethylacetamide, asdiluents in the process according to the invention.

When carrying out the process according to the invention for preparingcompounds of the formula (I), the reaction temperatures can be variedwithin a relatively wide range. The working temperatures are generallybetween −30° C. and +180° C., preferably between −10° C. and +150° C.,more preferably between 0° C. and 100° C.

The process according to the invention is generally carried out workingunder atmospheric pressure. However, it is also possible to work underelevated pressure or, as long as no volatile components are used, underreduced pressure.

To carry out the process according to the invention, generally between0.2 and 2 mol, preferably between 0.5 and 1.5 mol, of a dehydratingagent are used per mole of1-amino-6-hydroxy-3-phenyldihydro-2,4(1H,3H)pyrimidinedione derivativeof the formula (II).

In a preferred embodiment of the process according to the invention, theamino-6-hydroxy-3-phenyldihydro-2,4(1H,3H)pyrimidinedione derivative ofthe formula (II) is initially charged in a suitable diluent, and thedehydrating agent and also reaction assistants are metered in slowly.The reaction mixture is then stirred, optionally at elevatedtemperature, up to the end of the reaction. The workup is effected bycustomary methods (cf. the preparation examples).

The 1-amino-3-phenyluracil derivatives of the formula (I) can be used asherbicides for controlling weeds (cf. EP-A-648 749, WO-A-94/04511,WO-A-95/29168, WO-A-96/35679).

PREPARATION EXAMPLES Example 1

25.5 g (97.5%, 56.7 mMol) ofN-[5-(3-amino-4-hydroxy-2,6-dioxo-4-trifluoromethyl-tetrahydro-1(2H)-pyrimidinyl)-2-cyano-4-fluorophenyl]ethanesulphonamideare initially charged in 100 ml of n-butyronitrile and 224 mg (2.8 mMol)of pyridine are added at room temperature (approx. 20° C.). 33.7 g ofthionyl chloride are added dropwise to the suspension. Slight gasevolution takes place and the reaction mixture becomes yellow. Afterabout a minute, a clear solution has formed, cloudiness sets in afterabout 5 minutes and a voluminous precipitate has formed after about 10minutes. The mixture is heated to reflux temperature and stirred for afurther 30 minutes, and significant gas evolution sets in above about60° C. After cooling to room temperature, the mixture is diluted with 50ml of n-butyronitrile, 100 ml of ice-water are added, the phases areseparated, and the organic phase is washed three times with a littlewater, dried over sodium sulphate and filtered. The solvent is carefullydistilled off from the filtrate under reduced pressure.

22.6 g (94% according to 19F NMR quantification, 89% of theory) ofN-[5-(3-amino-2,6-dioxo-4-trifluoromethyl-3,6-dihydro-1(2H)-pyrimidinyl)-2-cyano-4-fluorophenyl]ethanesulphonamideof melting point 190° C. are obtained.

Starting Materials of the Formula (II) Example (II-1)

60.7 g (99.3%, 150 mmol) ofN-[2-cyano-5-(2,4-dioxo-6-trifluoromethyl-2H-1,3-oxazin-3(4H)-yl)-4-fluorophenyl]ethanesulphonamideare initially charged in 300 ml of propionic acid, and 9.0 g ofhydrazine hydrate (99%, 178 mmol) are added with stirring at roomtemperature (approx. 20° C.). The mixture (suspension) heats to approx.30° C. and the suspension is stirred at this temperature for 5 hours,while the colour lightens. The mixture is then cooled to 15° C. andfiltered with suction, and the filter residue is triturated with aspatula on the suction filter and washed repeatedly with isopropanol andsucked to dryness. The slightly yellowish filtercake is initially driedunder air and then overnight in a desiccator over potassium hydroxide.

41 g (94.9%, 60% of theory) ofN-[5-(3-amino-4-hydroxy-2,6-dioxo-4-trifluoromethyltetrahydro-1(2H)-pyrimidinyl)-2-cyano-4-fluorophenyl]ethanesulphonamidehaving a melting point of 182° C. (decomposition) are obtained.

After concentrating the mother liquor, the residue, according to HPLCanalysis, still contains 35.5% ofN-[5-(3-amino-4-hydroxy-2,6-dioxo-4-trifluoromethyltetrahydro-1(2H)-pyrimidinyl)-2-cyano-4-fluorophenyl]ethanesulphonamide(corresponds to a further 23% of the theoretical yield). This thereforeresults in a total yield of 83% of theory.

1. A process for preparing a compound of formula (I)

in which is hydrogen, cyano, nitro, or halogen, R² is cyano, nitro,halogen, or optionally substituted alkyl or alkoxy, R³ is hydrogen,hydroxyl, mercapto, amino, hydroxyamino, hydrazino, halogen, or one ofthe radicals —R⁶, -Q-R⁶, —NH—R⁶, —NH—O—R⁶, —NH—SO₂—R⁶, —N(SO₂—R⁶)₂,—CQ¹-R⁶, —CQ¹-Q²-R⁶, —CQ¹-NH—R⁶, -Q²-CQ¹-R⁶, —NH—CQ¹-R⁶,—N(SO₂—R⁶)(CQ¹-R⁶), -Q²-CQ¹-Q²-R⁶, —NH—CQ¹-Q²-R⁶, or -Q²-CQ¹-NH—R⁶,where Q is O, S, SO, or SO₂, Q¹ and Q² are each independently oxygen orsulphur, and R⁶ is optionally substituted alkyl, alkenyl, alkynyl,cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, heterocyclyl, orheterocyclylalkyl, R⁴ is hydrogen, halogen, or optionally substitutedalkyl, and R⁵ is fluorine- and/or chlorine-substituted alkyl, comprisingreacting a compound of formula (II)

in which R¹, R², R³, R⁴, and R⁵ are each as defined for formula (I),with a dehydrating agent at temperatures between −30° C. and +180° C. 2.A process according to claim 1 wherein for the compound of formula (II),R¹ is hydrogen, cyano, nitro, fluorine, chlorine, or bromine, R² iscyano, nitro, fluorine, chlorine, bromine, or optionally fluorine-and/or chlorine-substituted alkyl or alkoxy having 1 to 4 carbon atoms,R³ is hydrogen, hydroxyl, mercapto, amino, hydroxyamino, halogen, or oneof the radicals —R⁶, -Q-R⁶, —NH—R⁶, —NH—O—R⁶, —NH—SO₂—R⁶, —N(SO₂—R⁶)₂,—CQ¹-R⁶, —CQ¹-Q²-R⁶, —CQ¹-NH—R⁶, -Q²-CQ¹-R⁶, —NH—CQ¹-R⁶,—N(SO₂—R⁶)(CQ¹-R⁶), -Q²-CQ¹-Q²-R⁶, —NH—CQ¹-Q²-R⁶, or -Q²-CQ¹-NH—R⁶,where Q is O, S, SO, or SO₂, Q¹ and Q² are each independently oxygen orsulphur, and R⁶ is optionally cyano-, halogen-, C₁–C₄-alkoxy-,C₁–C₄-alkylthio-, C₁–C₄-alkylcarbonyl-, C₁–C₄-alkoxycarbonyl-, orC₁–C₄-alkylaminocarbonyl-substituted alkyl having 1 to 6 carbon atoms;or optionally cyano-, carboxy-, halogen-, C₁–C₄-alkylcarbonyl-,C₁–C₄-alkoxycarbonyl-, or C₁–C₄-alkylaminocarbonyl-substituted alkenylor alkynyl each having 2 to 6 carbon atoms; or optionally cyano,carboxy, halogen, C₁–C₄-alkylcarbonyl- orC₁–C₄-alkoxycarbonyl-substituted cycloalkyl or cycloalkylalkyl eachhaving 3 to 6 carbon atoms in the cycloalkyl group and 1 to 4 carbonatoms in the alkyl moiety; or optionally mono- to trihydroxy-,-mercapto-, -amino-, -cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-,—C₁–C₄-alkyl-, —C₁–C₄-haloalkyl-, —C₁–C₄-alkoxy-, —C₁–C₄-haloalkoxy-,—C₁–C₄-alkylthio-, —C₁–C₄-haloalkylthio-, —C₁–C₄-alkylsulphinyl-,—C₁–C₄-alkylsulphonyl-, —C₁–C₄-alkylamino-, and/or-dimethylamino-substituted aryl or arylalkyl each having 6 or 10 carbonatoms in the aryl group and 1 to 4 carbon atoms in the alkyl moiety; oroptionally mono- to tri-hydroxy-, -mercapto-, -amino-, -cyano-,-carboxy-, -carbamoyl-, -thiocarbamoyl-, —C₁–C₄-alkyl-,—C₁–C₄-haloalkyl-, —C₁–C₄-alkoxy-, —C₁–C₄-haloalkoxy-,—C₁–C₄-alkylthio-, —C₁-C₄-haloalkythio-, —C₁–C₄-alkylsulphinyl-,—C₁–C₄-alkylsulphonyl-, —C₁–C₄-alkylamino-, and/ordimethylamino-substituted heterocyclyl or heterocyclylalkyl having 2 to6 carbon atoms and 1 to 3 nitrogen atoms and/or 1 or 2 oxygen atomsand/or one sulphur atom in the heterocyclyl group and 1 to 4 carbonatoms in the alkyl moiety, R⁴ is hydrogen, fluorine, chlorine, bromine,or optionally fluorine- and/or chlorine-substituted alkyl having 1 to 6carbon atoms, and R⁵ is fluorine- and/or chlorine-substituted alkylhaving 1 to 6 carbon atoms.
 3. A process according to claim 1 whereinfor the compound of formula (II), R¹ is hydrogen, fluorine, or chlorine,R² is cyano, fluorine, chlorine, bromine, methyl, or trifluoromethyl, R³is hydroxyl, mercapto, amino, fluorine, chlorine, bromine, or one of theradicals —R⁶, -Q-R⁶, —NH—R⁶, —NH—O—R⁶, —NH—SO₂—R⁶, —N(SO₂—R⁶)₂, —CQ¹-R⁶,—CQ¹-Q²-R⁶, —CQ¹-NH—R⁶, -Q²-CQ¹-R⁶, —NH—CQ¹-R⁶, —N(SO₂—R⁶)(CQ¹-R⁶),-Q²-CQ¹-Q²-R⁶, —NH—CQ¹-Q²-R⁶, or -Q²-CQ¹-NH-R⁶, where Q is O, S, SO, orSO₂, Q¹ and Q² are each independently oxygen or sulphur, and R⁶ isoptionally cyano-, fluorine-, chlorine-, methoxy-, ethoxy-, methylthio-,ethylthio-, acetyl-, propionyl-, methoxycarbonyl-, ethoxycarbonyl-,methylaminocarbonyl-, or ethylaminocarbonyl-substituted methyl, ethyl,n- or i-propyl, or n-, i-, or s-butyl; or optionally cyano-, carboxy-,fluorine-, chlorine-, bromine-, acetyl-, propionyl-, n- or i-butyroyl-,methoxycarbonyl-, ethoxycarbonyl-, n- or i-propoxycarbonyl-,methylaminocarbonyl-, ethylaminocarbonyl-, or n- ori-propylaminocarbonyl-substituted propenyl, butenyl, propynyl, orbutynyl; or optionally cyano-, carboxy-, fluorine-, chlorine-, bromine-,acetyl-, propionyl-, methoxycarbonyl-, or ethoxycarbonyl-substitutedcyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopropylmethyl,cyclobutylmethyl, cyclopentylmethyl, or cyclohexylmethyl; or optionallymono- to trihydroxy-, -mercapto-, -amino-, -cyano-, -carboxy-,-carbamoyl-, -thiocarbamoyl-, -methyl-, -ethyl-, -trifluoromethyl-,-methoxy-, -ethoxy-, -difluoromethoxy-, -trifluoromethoxy-,-methylthio-, -ethylthio-, -difluoromethylthio-, -trifluoromethylthio-,-methylsulphinyl-, -ethylsulphinyl-, -methylsulphonyl-, -methylamino-,-ethylamino-, and/or -dimethylamino-substituted phenyl, benzyl, orphenylethyl; or optionally mono- or dihydroxy-, -mercapto-, -amino-,-cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-, -methyl-, -ethyl-, -n-or -i-propyl-, -n-, -i-, -s-, or -t-butyl-, -difluoromethyl-,-dichloromethyl-, -trifluoromethyl-, -trichloromethyl-,-chlorodifluoromethyl-, -fluorodichloromethyl-, -methoxy-, -ethoxy-,-difluoromethoxy-, -trifluoromethoxy-, -methylthio-, -ethylthio-,-difluoromethylthio-, -trifluoromethylthio-, -methylsulphinyl-,-ethylsulphinyl-, -methylsulphonyl-, -ethylsulphonyl-, -methylamino-,-ethylamino-, and/or -dimethylamino-substituted heterocyclyl orheterocyclylalkyl selected from the group consisting of oxiranyl,oxetanyl, furyl, tetrahydrofuryl, dioxolanyl, thienyl,tetrahydrothienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl,isoxazolyl, thiazolyl, isothiazolyl, oxadiazolyl, thiadiazolyl,pyridinyl, pyrimidinyl, triazinyl, pyrazolylmethyl, furylmethyl,thienylmethyl, oxazolylmethyl, isoxazolylmethyl, thiazolylmethyl,pyridinylmethyl, and pyrimidinylmethyl, R⁴ is hydrogen, fluorine,chlorine, bromine, methyl, ethyl, or trifluoromethyl, and R⁵ istrifluoromethyl, chlorodifluoromethyl, fluorodichloromethyl, orpentafluoroethyl.
 4. A compound of formula (II)

in which R¹ is hydrogen, cyano, nitro, or halogen, R² is cyano, nitro,halogen, or optionally substituted alkyl or alkoxy, R³ is hydrogen,hydroxyl, mercapto, amino, hydroxyamino, hydrazino, halogen, or one ofthe radicals —R⁶, -Q-R⁶, —NH—R⁶, —NH—O—R⁶, —NH—SO₂—R⁶, —N(SO₂—R⁶)₂,—CQ¹-R⁶, —CQ¹-Q²-R⁶, —CQ¹-NH—R⁶, Q²-CQ¹-R⁶, —NH—CQ¹-R⁶,—N(SO₂—R⁶)(CQ¹-R⁶), -Q²-CQ¹-Q²-R⁶, —NH—CQ¹-Q²-R⁶, or -Q²-CQ¹-NH—R⁶,where Q is O, S, SO, or SO₂, Q¹ and Q² are each independently oxygen orsulphur, and R⁶ is optionally substituted alkyl, alkenyl, alkynyl,cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, heterocyclyl, orheterocyclylalkyl, R⁴ is hydrogen, halogen, or optionally substitutedalkyl, and R⁵ is fluorine- and/or chlorine-substituted alkyl.
 5. Acompound of formula (II) according to claim 4 in which R¹ is hydrogen,cyano, nitro, fluorine, chlorine, or bromine, R² is cyano, nitro,fluorine, chlorine, bromine, or optionally fluorine- and/orchlorine-substituted alkyl or alkoxy having 1 to 4 carbon atoms, R³ ishydrogen, hydroxyl, mercapto, amino, hydroxyamino, halogen, or one ofthe radicals —R⁶, -Q-R⁶, —NH—R⁶, —NH—O—R⁶, —NH—SO₂—R⁶, —N(SO₂—R⁶)₂,—CQ¹-R⁶, —CQ¹-Q²-R⁶, —CQ¹-NH—R⁶, —Q²-CQ¹-R⁶, —NH—CQ¹-R⁶,—N(SO₂—R⁶)(CQ¹-R⁶), -Q²-CQ¹-Q²-R⁶, —NH—CQ¹-Q²-R⁶, or -Q²-CQ¹-NH—R⁶,where Q is O, S, SO, or SO₂, Q¹ and Q² are each independently oxygen orsulphur, and R⁶ is optionally cyano-, halogen-, C₁–C₄-alkoxy-,C₁–C₄-alkylthio-, C₁–C₄-alkylcarbonyl-, C₁–C₄-alkoxycarbonyl-, orC₁–C₄-alkylaminocarbonyl-substituted alkyl having 1 to 6 carbon atoms;or optionally cyano-, carboxy-, halogen-, C₁–C₄-alkylcarbonyl-,C₁–C₄-alkoxycarbonyl-, or C₁–C₄-alkylaminocarbonyl-substituted alkenylor alkynyl each having 2 to 6 carbon atoms; or optionally cyano,carboxy, halogen, C₁–C₄-alkylcarbonyl- orC₁–C₄-alkoxycarbonyl-substituted cycloalkyl or cycloalkylalkyl eachhaving 3 to 6 carbon atoms in the cycloalkyl group and 1 to 4 carbonatoms in the alkyl moiety; or optionally mono- to trihydroxy-,-mercapto-, -amino-, -cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-,—C₁–C₄-alkyl-, —C₁–C₄-haloalkyl-, —C₁–C₄-alkoxy-, —C₁–C₄-haloalkoxy-,—C₁–C₄-alkylthio-, —C₁–C₄-haloalkylthio-, —C₁–C₄-alkylsulphinyl-,—C₁–C₄-alkylsulphonyl-, —C₁–C₄-alkylamino-, and/or-dimethylamino-substituted aryl or arylalkyl each having 6 or 10 carbonatoms in the aryl group and 1 to 4 carbon atoms in the alkyl moiety; oroptionally mono- to tri-hydroxy-, -mercapto-, -amino-, -cyano-,-carboxy-, -carbamoyl-, -thiocarbamoyl-, —C₁–C₄-alkyl-,—C₁–C₄-haloalkyl-, —C₁–C₄-alkoxy-, —C₁–C₄-haloalkoxy-,—C₁–C₄-alkylthio-, —C₁–C₄-haloalkylthio-, —C₁–C₄-alkylsulphinyl-,—C₁–C₄-alkylsulphonyl-, —C₁–C₄-alkylamino-, and/ordimethylamino-substituted heterocyclyl or heterocyclylalky having 2 to 6carbon atoms and 1 to 3 nitrogen atoms and/or 1 or 2 oxygen atoms and/orone sulphur atom in the heterocyclyl group and 1 to 4 carbon atoms inthe alkyl moiety, R⁴ is hydrogen, fluorine, chlorine, bromine, oroptionally fluorine- and/or chlorine-substituted alkyl having 1 to 6carbon atoms, and R⁵ is fluorine- and/or chlorine-substituted alkylhaving 1 to 6 carbon atoms.
 6. A compound of formula (II) according toclaim 4 in which R¹ is hydrogen, fluorine, or chlorine, R² is cyano,fluorine, chlorine, bromine, methyl, or trifluoromethyl, R³ is hydroxyl,mercapto, amino, fluorine, chlorine, bromine, or one of the radicals—R⁶, -Q-R⁶, —NH—R⁶, —NH—O—R⁶, —NH—SO₂—R⁶, —N(SO₂—R⁶)₂, —CQ¹-R⁶,—CQ¹-Q²-R⁶, —CQ¹-NH—R⁶, —Q²-CQ¹-R⁶, —NH—CQ¹-R⁶, —N(SO₂—R⁶)(CQ¹-R⁶),-Q²-CQ¹-Q²-R⁶, —NH—CQ¹-Q²-R⁶, or -Q²-CQ¹-NH—R⁶, where Q is O, S, SO, orSO₂, Q¹ and Q² are each independently oxygen or sulphur, and R⁶ isoptionally cyano-, fluorine-, chlorine-, methoxy-, ethoxy-, methylthio-,ethylthio-, acetyl-, propionyl-, methoxycarbonyl-, ethoxycarbonyl-,methylaminocarbonyl-, or ethylaminocarbonyl-substituted methyl, ethyl,n- or i-propyl, or n-, i-, or s-butyl; or optionally cyano-, carboxy-,fluorine-, chlorine-, bromine-, acetyl-, propionyl-, n- or i-butyroyl-,methoxycarbonyl-, ethoxycarbonyl-, n- or i-propoxycarbonyl-,methylaminocarbonyl-, ethylaminocarbonyl-, or n- or-propylaminocarbonyl-substituted propenyl, butenyl, propynyl, orbutynyl; or optionally cyano-, carboxy-, fluorine-, chlorine-, bromine-,acetyl-, propionyl-, methoxycarbonyl-, or ethoxycarbonyl-substitutedcyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopropylmethyl,cyclobutylmethyl, cyclopentylmethyl, or cyclohexylmethyl; or optionallymono- to trihydroxy-, -mercapto-, -amino-, -cyano-, -carboxy-,-carbamoyl-, -thiocarbamoyl-, -methyl-, -ethyl-, -trifluoromethyl-,-methoxy-, -ethoxy-, -difluoromethoxy-, -trifluoromethoxy-,-methylthio-, -ethylthio-, -difluoromethylthio-, -trifluoromethylthio-,-methylsulphinyl-, -ethylsulphinyl-, -methylsulphonyl-, -methylamino-,-ethylamino-, and/or -dimethylamino-substituted phenyl, benzyl, orphenylethyl; or optionally mono- or di-hydroxy-, -mercapto-, -amino-,-cyano-, -carboxy-, -carbamoyl-, -thiocarbamoyl-, -methyl-, -ethyl-, -n-or -i-propyl-, -n-, -i-, -s-, or -t-butyl-, -difluoromethyl-,-dichloromethyl-, -trifluoromethyl-, -trichloromethyl-,-chlorodifluoromethyl-, -fluorodichloromethyl-, -methoxy-, -ethoxy-,-difluoromethoxy-, -trifluoromethoxy-, -methylthio-, -ethylthio-,-difluoromethylthio-, -trifluoromethylthio-, -methylsulphinyl-,-ethylsulphinyl-, -methylsulphonyl-, -ethylsulphonyl-, -methylamino-,-ethylamino-, and/or -dimethylamino-substituted heterocyclyl orheterocyclylalkyl selected from the group consisting of oxiranyl,oxetanyl, furyl, tetrahydrofuryl, dioxolanyl, thienyl,tetrahydrothienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl,isoxazolyl, thiazolyl, isothiazolyl, oxadiazolyl, thiadiazolyl,pyridinyl, pyrimidinyl, triazinyl, pyrazolylmethyl, furylmethylthienylmethyl, oxazolylmethyl, isoxazolylmethyl, thiazolylmethyl,pyridinylmethyl, and pyrimidinylmethyl, R⁴ is hydrogen, fluorine,chlorine, bromine, methyl, ethyl, or trifluoromethyl, and R⁵ istrifluoromethyl, chlorodifluoromethyl, fluorodichloromethyl, orpentafluoroethyl.
 7. A process for preparing a compound of formula (II)according to claim 4 comprising reacting a compound of formula (III)

in which R¹, R², R³, R⁴, and R⁵ are each as defined for formula (II) inclaim 4, with hydrazine, hydrazine hydrate, or an acid adduct ofhydrazine at temperatures between −30° C. and +100° C.
 8. A processaccording to claim 1 carried out in the presence of one or more reactionassistants.
 9. A process according to claim 1 carried out in thepresence of one or more diluents.
 10. A process according to claim 9wherein the diluent is an aprotic polar solvent.
 11. A process accordingto claim 8 carried out in the presence of one or more diluents.
 12. Aprocess according to claim 11 wherein the diluent is an aprotic polarsolvent.
 13. A process according to claim 1 wherein the dehydratingagent is a carbodiimide, orthoester, acid, acid anhydride, acidchloride, or Lewis acid.
 14. A process according to claim 1 wherein thedehydrating agent is thionyl chloride.
 15. A process according to claim8 wherein the reaction assistant is a basic organic nitrogen compound.16. A process according to claim 8 wherein the reaction assistant ispyridine.
 17. A process according to claim 1 carried out at temperaturesbetween −10° C. and +150° C.